School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, P. R. China.
Angew Chem Int Ed Engl. 2023 Jun 19;62(25):e202303102. doi: 10.1002/anie.202303102. Epub 2023 May 9.
Preserving large permanent pore structures in a fluid may endow conventional liquids with emergent physical properties. However, such materials are challenging to make because of the tendency of the pores to be filled and occupied by the solvent molecules. Here, we report the design and synthesis of the first Type III porous liquid (PL) containing uniform yet stable 480 nm cavities. This was achieved by first constructing a single crystalline hollow metal-organic framework (MOF), UiO-66-NH , through chemical etching. The thin yet defect-free MOF shell effectively excludes the bulky poly(dimethylsiloxane) solvent molecules from entering the cavity through its 4 Å aperture, resulting in the preservation of both micro- and macroporosity in the PL. These enormous void spaces allow the PL to reversibly host and release up to 27 wt % water for up to 10 cycles. The switching between the "dry" state and the "wet" state led to a large changes of the thermal conductivity of the PL from 0.140 to 0.256 W m K , affording a guest-responsive liquid thermal switch with a switching ratio of 1.8.
在流体中保留大的永久孔结构可以赋予常规液体新的物理特性。然而，由于孔倾向于被溶剂分子填充和占据，因此制造这种材料具有挑战性。在这里，我们报告了第一个含有均匀且稳定的 480nm 空腔的 III 型多孔液体（PL）的设计和合成。这是通过首先通过化学刻蚀构建单个结晶的中空金属有机骨架（MOF）UiO-66-NH 来实现的。薄而无缺陷的 MOF 壳有效地阻止了体积庞大的聚二甲基硅氧烷溶剂分子通过其 4Å 的孔径进入空腔，从而在 PL 中保留了微孔和大孔。这些巨大的空隙空间允许 PL 可逆地容纳和释放高达 27wt%的水，多达 10 个循环。在“干燥”状态和“湿润”状态之间的切换导致 PL 的热导率从 0.140 增加到 0.256Wm-1K-1，从而提供了具有 1.8 切换比的客响应液体热开关。
